define mean and variance?

Question

mean and variance definition in random variable in probability

Answer 1

The mean of a discrete random variable X is a weighted average of the possible values that the random variable can take.    μ_x=Σx_ip_i   in other words its the sum of all random variables times their probabilities 

 

 

The variance of a discrete random variable X measures the spread, or variability, of the distribution, and is defined by  σ²_x= Σ(x_i - μ_x)²